ABSTRACT
Deficits in attention and concentration are reported to be among the most common symptoms following head injury. Various underlying mechanisms of selective attention such as excitation, inhibition, and habituation have been isolated in recent studies. In the present study 27 control and 25 closed-head-injured (CHI) subjects were compared on four conditions based on the Stroop color-word task (neutral, habituation, Stroop, and negative priming). Cross-comparison of the different tasks enables examination of the various components of selective attention. The hypothesis that the control group's overall reading time would be faster than that of the CHI group was confirmed. Also confirmed was the hypothesis that the overall reading time pattern between task conditions would be neutral < habituation < Stroop < negative priming. The prediction that the CHI patients, due to their impaired inhibitory mechanism, would not show a slower reading time on the negative priming as compared to the Stroop condition, was confirmed as well. The theoretical and diagnostic implications of the results are discussed.
Subject(s)
Attention , Color Perception , Discrimination Learning , Head Injuries, Closed/psychology , Semantics , Adolescent , Adult , Female , Habituation, Psychophysiologic , Humans , Male , Middle AgedABSTRACT
We analysed the cytotoxic effect of city smog extracts from a heavy industrialized area using kidney cell cultures from the primate Cercopithecus aethiops.--Using logarithmically growing cell cultures we determined cell replication and the rate of DNA-synthesis after incorporation of 3H-thymidine.--In presence of city smog extracts we found a dose dependent reduction of cell replication and of DNA-synthesis. In presence of high concentrations (BP-aquivalent 0.25-0.5 microgram/ml) of city smog extract we found no increase in cell number over a period of 72 h. Under the same conditions hardly any DNA-synthesis was detected.--In presence of middle and low concentrations of city smog extract a dose- and time-dependent increase in cell number and rate of DNA-synthesis was detected.
Subject(s)
Benzopyrenes/pharmacology , Cell Division/drug effects , DNA/biosynthesis , Smog , Animals , Cercopithecus , Culture Techniques , Germany, West , Haplorhini , KidneyABSTRACT
A city smog extract from an urban area inhibits the cell growth of hamster kidney cells in vitro. Parallel to an inhibition of cell multiplication a diminished rate of total DNA synthesis appeared. The number of cells in DNA synthesis is depressed in presence of city smog extract. These phenomena revealed a dose-response relationship. The biological effect of city smog extract is discussed.
Subject(s)
Benzopyrenes/pharmacology , Cell Division/drug effects , DNA Replication/drug effects , DNA/biosynthesis , Smog , Animals , Cell Line , Cricetinae , Dose-Response Relationship, Drug , MesocricetusABSTRACT
We analyzed the cytotoxic effect of a city smog extract from a large urban area, employing mouse macrophages in vitro. In parallel experiments we tested carcinogenic and non carcinogenic polycyclic aromatic hydrocarbons: benzo(a)pyrene, 7, 12-dimethylbenzanthracene, pyrene and anthracene. City smog extract induced a dose-dependent reduction of cell viability and an alteration in cell membrane permeability. In contrast to city smog extract the carcinogenic and non carcinogenic polycyclic aromatic hydrocarbons produced no detectable cytotoxic effects in the dose range we analyzed. Possible implications of the cytotoxic effect of city smog extract on the lung are discussed.
Subject(s)
Air Pollutants/adverse effects , Macrophages/drug effects , Urban Population , Air Pollution/analysis , Animals , Anthracenes/adverse effects , Benzopyrenes/adverse effects , Carcinogens , Dust , Germany, West , Mice , Mutagens/adverse effects , Pyrenes/adverse effects , Smog/analysisSubject(s)
Copper/analysis , Histidine/analysis , Luminol , Pyridazines , Catalysis , Chemical Phenomena , Chemistry , Hydrogen Peroxide , Kinetics , Luminescent Measurements , Spectrometry, FluorescenceSubject(s)
Sulfates/analysis , Ascorbic Acid , Barium , Chemistry Techniques, Analytical , ChromatesSubject(s)
Benzopyrenes/analysis , Dust/analysis , Lung/analysis , Adult , Age Factors , Aged , Female , Germany, West , Humans , Male , Middle Aged , Mining , Pneumoconiosis/diagnosisSubject(s)
Copper/analysis , Cystine/analysis , Azides , Catalysis , Iodine , Iron , Kinetics , Methods , Spectrophotometry , ThiosulfatesABSTRACT
A new variation of isotope dilution analysis based on double labelling and carried out on filter paper is described. The determination of microgram and submicrogram amounts of silver (labelled with (110m)Ag) by precipitation with iodide (labelled with (131)I) and of calcium (labelled with (45)Ca) by precipitation with phosphate (labelled with (32)P) are given as examples. In the first example the two radio-elements ((110m)Ag and (131)I) are measured by gamma-spectrometry, in the second one ((45)Ca and(32)P) by a beta-absorption method. A number of results show the usefulness of the method.
ABSTRACT
A kinetic method is described for the determination of molybdenum by its catalytic effect on the peroxide-iodide reaction. The reaction rate is kept constant by adding iodide at the same rate as it is being consumed, the concentration being kept constant by a potentiostat. The rate of the addition of iodide is then proportional to the molybdenum concentration. The element was determined in the range 0.5-11 mug in 50 ml.
